This proposal is designed to further our understanding of the contribution of the orbital prefrontal cortex (PFCx) to human social behavior. Techniques drawn from cognitive neuroscience will be used in an effort to integrate information processing theories of social adjustment with theories of emotional influences on cognition. Neuropsychological and high field functional neuroimaging (4T) approaches will be employed to examine the contribution of orbital PFCx to the interplay of emotional response on two on-line predictors of social adjustment: decision making and judgment of social stimuli. Neuropsychological studies in patients with discrete damage in orbital PFCx examine the involvement of this region in emotional biasing of social decisions and judgments. Functional neuroimaging studies in healthy controls will assess whether there is evidence of activation in orbital PFCx in these tasks. The experimental approach is designed to provide converging lesion and fMRI information on the role of orbital PFCx in social behavior. The proposed research draws on paradigms for eliciting emotion and examining decisions and judgments that have been used extensively in previous research. Well-validated tasks assessing risky decisions and judgments of social behavior that are susceptible to emotional bias will also be implemented. Risky decision making will be assessed using the Perceptions of Risk Questionnaire and a roulette gambling task. Judgments of social behavior will be assessed using the Profile of Nonverbal Sensitivity and the Pictures of Facial Affect Set. The proposed research represents a novel application of these paradigms because previous studies have not attempted to systematically relate these processes to activity in brain areas felt to be implicated in social adjustment. The proposal is designed to provide a basis for developing a larger program of research aimed at understanding the neural basis of social behavior.